Carb issues (UPDATE) 2nd UPDATE

[sandy]

'99 tourer with 50K. A friend had to quit riding for a few months due to injuries. Jets got clogged so we R&Rd the carb bank this past weekend. Cleaned out all 12 jets and reassembled. New intake O rings (Viton) and vacuum lines (Honda OEM). Started and idled fine. About 1500 -3000 RPMs, it stutters and pops under light throttle input. When you get on it, no issues. Installed new plugs which helped a little (smoother running). Floats appeared good. Set pilots to 2 turns out. He has glasspacks and a K&N filter (no other mods). Any suggestions on the source of popping??
WE R&R'D THE DIAPHRAGMS AND FOUND NO PROBLEMS BUT THE #2 CARB ISN'T DELIVERING FUEL. WHEN WE PULLED THE PLUG WIRE, WE HAD SPARK BUT IT MADE NO DIFFERENCE IN THE WAY IT RUNS (STUMBLES).
R&R'd the carbs again today(1/18) , Did a more thorough disassembly and soaked all ports and blew them out. The #2 had a deeply clogged port. It took several soaks and blows to finally clear it. Ed rode home and called me. He's happy now. BTW: We removed the ABV on #2 and flushed it too, but I don't think that was the issue.

[Ricky-D]

I always tend to think when this happens is because the low speed circuits are clogged.

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[Hook#3287]

After swapping over to 38's, and desmogging, I've never had that issue again on 6 different Valks.

I didn't have luck with "Cleaning" jets.

Some have done it, but it didn't work for me and I had to do the job twice.

[9Ball]

After swapping over to 38's, and desmogging, I've never had that issue again on 6 different Valks.

I didn't have luck with "Cleaning" jets.

Some have done it, but it didn't work for me and I had to do the job twice.

That’s been my exact experience too...good advice to replace with new.  If problems still exist at least you will know it’s not the jets faults.

[Fla. Jim]

The only chemical cleaner that has worked for me. And it did. Even after having them professionally rebuilt by someone well known here, was Chevron Techron. Guess even soaking in a vat of cleaner and having the Jets replaced was not my problem. So sometimes chemicals will do a job better depending I guess on the chems used.

[rug_burn]

    All good advice in my experience, too.   I have had to open the low range screws, some to as much as 4 turns or more.   I must have a partially plugged channel or line somewhere.     
     I also took off the diaphragm covers, took out and cleaned the needles just by scratching them with my fingernail.    And they mostly all needed it, they had a layer of glazed gum or something on them which came off easily.     Then while I had the cover off, I took a .099 or .101 dia drill in a pin vise, and very lightly reamed the main jet to get out any crud from that.
     Still, it's taken a long time to get mine running to (mostly) as good as before I let it get clogged up, adjusting mixtures and idle vacuum adjustments.
    In  the middle of this, I found one of my newly replaced 3.5mm vacuum lines had a hole in it, apparently from some of the carb cleaners I tried, and I tried just about every one out there.

[TTG53#1717]

Is it possible you kinked a slide return spring when you put the carbs back together ?

That’s what happened to me and it exhibited those same stumbles and pops up to 3k.
The slide was not able to fully seat, but had no problems going further up.

Once it got above 3k and was able to match the other 5 carbs it smoothed right out.

[Jims99]

I use gum cutter for cleaning. Do not get it on rubber o rings and gaskets, will eat them up.
I used on a 63 Ford carb that was totally frozen, sprayed it down and could move all parts the next morning. I’ve been using it for years now and love it. (Just keep away from rubber) Will remove all the varnish and crud that builds up.